NBFM (Was: AM on sBITX?)

Rafael Diniz All Messages By This Member #113582 Btw, I was thinking in adding NBFM. Did anyone already implemented it? - Rafael toggle quoted message Show quoted text On 9/13/24 7:48 AM, JJ - W9JES wrote: The link contains information on downloading our version and/or image. It contains AM RX and TX. Here is an example of RX in the AM broadcast band. It also works as TX/RX in the amateur bands. OpenPGP_signature.asc OpenPGP_signature.asc
JJ - W9JES All Messages By This Member #114102 Not yet... I'd love to see NBFM on this platform so I can effectively use my transverter for other modes.
WP3DN All Messages By This Member #114105 Rafael,? ? I also have a 2m working system. If you would like to test any implementation of nbfm or any other mode let me know. ? Juan WP3DN
Rafael Diniz All Messages By This Member #114107 But why are you not using NBFM with sBitx? Its bandwidth is by far much wider than what is needed for NBFM. - Rafael PU2UIT toggle quoted message Show quoted text On 10/29/24 2:14 AM, WP3DN wrote: Rafael, I also have a 2m working system. If you would like to test any implementation of nbfm or any other mode let me know. Juan WP3DN OpenPGP_signature.asc OpenPGP_signature.asc
WP3DN All Messages By This Member #114108 Rafael,? ? But how to add the mode is the question. ? Juan WP3DN
Jon / W2JON All Messages By This Member #114109 I was considering taking this on a month or so back, But I have not yet had the time to commit to the project due to other responsibilities. ? ? ?
Rafael Diniz All Messages By This Member #114110 Most of SDR software already has NBFM. Do you want to implement it yourself? - Rafael toggle quoted message Show quoted text On 10/29/24 10:49 AM, WP3DN wrote: Rafael, But how to add the mode is the question. Juan WP3DN OpenPGP_signature.asc OpenPGP_signature.asc
WP3DN All Messages By This Member #114111 Rafael,? ? How to add it to sbitx software. Did not explain myself right. I have a 2m radio using the sbitx software. That is why I asked about the fm mode. ? Juan WP3DN
Gordon Gibby KX4Z All Messages By This Member #114112 It would be really NICE to have it added to the sBitx.... Gordon KX4Z toggle quoted message Show quoted text On Tue, Oct 29, 2024 at 8:54?AM WP3DN via <3voltios=[email protected]> wrote: Rafael,? ? How to add it to sbitx software. Did not explain myself right. I have a 2m radio using the sbitx software. That is why I asked about the fm mode. ? Juan WP3DN
Jon / W2JON All Messages By This Member #114119 Since FM detection typically requires the I (in phase) and Q (quadrature) samples to measure frequency deviation we can’t really use a typical quadrature detector without Q? I’m thinking a synthetic quadrature detector may do the trick. I think we should be able to approximate FM demodulation by generating a synthetic Q using Hilbert transform or a differentiator. Maybe I’m wrong, and that is something I am often…But this might be an approach I’d take a stab at. ?
Evan Hand All Messages By This Member #114120 The FFT transforms should make it possible to decode/encode the FM deviation from/to an audio signal.? The encoding process zeroes all the frequency bins and then places a value in the bin that corresponds to the audio level.? Decoding involves finding the peak in the frequency domain and converting it to an audio level. ? The above is a thought experiment so that I could be wrong. ? 73 Evan AC9TU
Rafael Diniz All Messages By This Member #114124 Or even with the use of a library for demoding nbfm, like csdr. - Rafael toggle quoted message Show quoted text On 10/30/24 9:08 AM, Evan Hand wrote: The FFT transforms should make it possible to decode/encode the FM deviation from/to an audio signal.? The encoding process zeroes all the frequency bins and then places a value in the bin that corresponds to the audio level.? Decoding involves finding the peak in the frequency domain and converting it to an audio level. The above is a thought experiment so that I could be wrong. 73 Evan AC9TU OpenPGP_signature.asc OpenPGP_signature.asc
Evan Hand All Messages By This Member #114130 Hello Rafael, ? I believe that the csdr libraries require an I/Q (90-degree phase shifted) signal.? The sBitx does not have that available unless code is written to do the Tayloe decoding in software.? That could be easier than what I am suggesting.? I do not have the skills to do that from scratch. ? I just got my DE working again, so I will try my suggestion after I have upgraded the software to JJ's 64-bit version.? That may be a couple of weeks as I do not get much radio time with the support needs of my wife after knee replacement surgery. ? 73 Evan AC9TU
Jon / W2JON All Messages By This Member #114133 The frequency differentiation method would be able to approximate the phase difference by using consecutive I samples. But the demod product would probably be pretty crappy at best. I think that the transform method should at least be able to simulate a phased Q sample which may be a bit better as a starting point. I messed with this a while ago when I was offloading a synthetic IQ stream to SDRAngel. it almost worked, but I lost interest in the challenge..?
Rafael Diniz All Messages By This Member #114138 Do it does not require I/Q. It works pretty fine indeed, already tested. : ) toggle quoted message Show quoted text On 10/30/24 9:43 PM, Evan Hand wrote: Hello Rafael, I believe that the csdr libraries require an I/Q (90-degree phase shifted) signal.? The sBitx does not have that available unless code is written to do the Tayloe decoding in software. That could be easier than what I am suggesting.? I do not have the skills to do that from scratch. I just got my DE working again, so I will try my suggestion after I have upgraded the software to JJ's 64-bit version.? That may be a couple of weeks as I do not get much radio time with the support needs of my wife after knee replacement surgery. 73 Evan AC9TU OpenPGP_signature.asc OpenPGP_signature.asc
Evan Hand All Messages By This Member #114139 Hi Rafael, ? Thank you for the feedback.? I will look into it. ? 73 Evan AC9TU
Rafael Diniz All Messages By This Member #114140 Hi Evan, I maintain this fork of it (just compilation fixes): and packages for arm64 (run on any 64 bit image): - Rafael toggle quoted message Show quoted text On 10/31/24 10:00 AM, Evan Hand wrote: Hi Rafael, Thank you for the feedback.? I will look into it. 73 Evan AC9TU OpenPGP_signature.asc OpenPGP_signature.asc
Evan Hand All Messages By This Member #114141 Hi Rafael, ? Thank you for the links! ? I have had a setback with my DE, so I cannot try this until I repair the low-power problems. ? 73 Evan AC9TU
Ashhar Farhan All Messages By This Member #114142 I/Q is one way. Here is a simpler way: 1. The signal is essentially AC. 2. Mark the exact time at which the signal transits from positive to negative. 3. This measures the time period of every crest and trough of the signal. 4. When the signal frequency is low, the time periods are lengthier. When the signal frequency is higher, the time period is smaller. 5. The time period is our demodulated signal. - f toggle quoted message Show quoted text On Thu, Oct 31, 2024, 5:32 AM Jon / W2JON via <sigmazgfx=[email protected]> wrote: The frequency differentiation method would be able to approximate the phase difference by using consecutive I samples. But the demod product would probably be pretty crappy at best. I think that the transform method should at least be able to simulate a phased Q sample which may be a bit better as a starting point. I messed with this a while ago when I was offloading a synthetic IQ stream to SDRAngel. it almost worked, but I lost interest in the challenge..?

Previous Topic Next Topic

开云体育

NBFM (Was: AM on sBITX?)